Many thanks for the information.
I actually found a member on here who has a more modern version of the manual for the Aciera F3 mill it is for and this says ISO 150, so as you both said.
My next question is I have to buy 20 liters of Castrol Hyspin 100 for my lathe, this is ISO 100 , would this be ok to use in the mill instead of ISO 150?
Thanks.